WTA Finals getting more interesting

Defending champion @ElinaSvitolina advances to the @SHISEIDO_corp @WTAFinals semifinals with straight-set victory over Simona Halep --> https://t.co/lNooNymYUF pic.twitter.com/pEwNds22cj

— WTA (@WTA) October 30, 2019

I doubt if anyone was surprised when 4th seed Bianca Andreescu retired today after the first set in her WTA Finals round robin match against Karolina Pliskova. The U.S. Open champion has a back injury that was evident when she lost to Simona Halep a few days ago; today, though, she had top stop playing because of a knee injury. But Andreescu isn't alone; yesterday, 3rd seed Naomi Osaka withdrew from the event and was replaced by first alternate Kiki Bertens. Bertens wasted no time, and knocked out top seed Ash Barty in straight sets.

Today, 8the seed and defending champion Elina Svitolina, playing in the purple group, defeated Simona Halep in straight sets, and became the first of the eight competitors to reach the semifinals.

Here is the current state of both the singles and doubles draws:

SINGLES

Red Group

Ashleigh Barty (1): 1-1
Naomi Osaka (3): 1-0, withdrawn from tournament
Belinda Bencic (7): 1-1
Petra Kvitova (6): 0-2
Kiki Bertens (1st alternate): 1-0

Purple Group

Elina Svitolina* (8): 2-0
Simona Halep (5): 1-1
Karolina Pliskova (2): 1-1
Bianca Andreescu (4): 0-2, withdrawn from tournament

DOUBLES

Red Group

Groenefeld/Schuurs (8): 1-1
Mertens/Sabalenka (1): 1-1
Babos/Mladenovic** (3): 2-0
Chan/Chan (5): 0-2

Purple Group

Hsieh/Strycova (2): 2-0
Stosur/Zhang (7): 2-0
Krejcikova/Siniakova (6): 1-1
Dabrowski/Xu (4): 0-2

*defending champion
**defending champions